Security inspection is of great significance in the fields of anti-terrorism and the fight against drug trafficking and smuggling, etc. People have been paying much more attention to security inspection on civil aviation since the U.S. Sep. 11, 2001 attacks. With the comprehensive development of the fight against drug trafficking and smuggling, the requirement for the inspection of air container and railway baggage etc. is much more stringent.
With reference to FIGS. 8, 9, 10, 11A, 11B and 11C, a vehicle-mounted imaging system 1000 previously used by the present applicants generally includes a vehicle 600 carrying the imaging system 1000 and an arm-folding mechanism 44. The vehicle 600 includes a vehicle body and a driving cab 42. The vehicle body is divided into a generator cabin 41 and a detection system control cabin 40 along the traveling direction A of the vehicle. The arm-folding mechanism 44, when in a folded state, is compactly disposed on the top of the vehicle body as shown in FIG. 9 so as to be carried and transported by the vehicle to places in need. A vertical detection arm of the arm-folding mechanism 44 is positioned on an equipment room. There is no spatial requirement for the equipment room, so the equipment room can be provided very low such that the folded vertical detection arm can be placed on top of it. The folded vertical detection arm is usually located on the side face of the main arm frame of the arm-folding mechanism 44 and the lowest point of the vertical detection arm is lower than the lowest point of the main arm frame. A revolving bearing portion of the main arm frame is positioned above the generator cabin and extends slantways downwards from the main arm frame to be lower than the plane on which the highest point of the top of the generator cabin is, so the top of the generator cabin has to be made into a stepped shape, i.e., it has two parallel planes at different heights. Thus, in such a vehicle-mounted imaging system, the revolving point of the original arm-folding mechanism occupies some space of the cabin, and a relatively larger subsidiary arm frame occupies more space of the cabin. The manufacture and processing of such a generator cabin is complex so that the cost of production is high.
The generator cabin 41 is close to the driving cab 42. An accelerator is located at the position of a passage formed by the unfolded vertical detection arm and the main arm frame so as to carry out radiation imaging detection, so the control cabin 40 is close to the accelerator, resulting in a harmful influence of radiation to an operator. The generator cabin 41 is not a human-operating area, so the generator cabin 41 configured to have a low area has no other defects except the complexity in production. However, in order to achieve a certain radiation protection level, the design of the system consequentially makes the control cabin 40 in the status of detection closer to the accelerator so that the walls and top of the control cabin need more anti-radiation materials. Hence, the load of the vehicle-mounted system is increased, the adaptability of the vehicle-mounted system to the vehicle load limitation regulations of each country is reduced, and the cost of production is increased.
When the arm-folding mechanism is in use, the folded arm-folding mechanism firstly needs to be rotated, within a plane that is parallel to the ground surface, about 90° from the vehicle body so that the arm-folding mechanism is substantially perpendicular to the traveling direction of the vehicle, and then the vertical detection arm is rotated downwards about 90° so that the vertical detection arm is substantially perpendicular to the main arm frame as well as the ground surface, as shown in FIG. 8. At this time, the arm-folding mechanism is unfolded, and the vertical detection arm is on one side of the vehicle and hung on the main arm frame by a hinged mechanism such that a detection passage area 500 for allowing the passage of the objects to be detected is formed. The equipment room rotatably moves to the other side of the vehicle body, and the operator in the control cabin 40 makes corresponding control operation.